The invention resides in a fuel injection nozzle for an internal combustion engine with direct fuel injection including a nozzle housing with a nozzle seat, a nozzle needle with a conical closure body which, in its closed position, engages a seal surface formed on the nozzle seat but is movable axially outwardly by the nozzle needle for opening the nozzle to form a gap through which a hollow conical fuel jet is discharged from the nozzle into a combustion chamber of the engine.
In the operation of new spark ignition internal combustion engines with direct fuel injection the mixture formation in the combustion chambers has been improved by the use of modern fuel injection nozzles wherein, however, manufacturing tolerances affect the combustion and the formation of emissions.
DE 196 42 653 C1 discloses a method for forming a fuel mixture in an internal combustion engine with direct fuel injection wherein the fuel is injected during an opening stroke of a valve member relative to a valve seat of an injector and wherein the injection time is variably adjustable and the injection angle and also the fuel volume flow can be dynamically influenced.
Furthermore, DE 100 12 97 A1 discloses a method of forming an ignitable fuel mixture wherein the fuel is introduced into the combustion chamber of an internal combustion engine in at least two partial amounts by way of an injection nozzle with a closure body which is returned to its closing position after the injection procedure of each partial amount. The fuel jet is accelerated up to the exit from the nozzle since the nozzle opening has a curved or parabola-shaped discharge area which narrows down the nozzle opening uniformly up to the exit end.
Since different fuel injection nozzles generate, because of manufacturing tolerances, differently shaped fuel jets which affect the mixture formation and consequently the combustion process in different ways, before the installation of the injection nozzles into an internal combustion engine the respective geometries of the nozzles would have to be corrected that is adapted to one another, which is hardly possible.
It is the object of the present invention to provide for simple means on the fuel injection nozzle of an internal combustion engine with direct fuel injection whereby an improved combustion process can be achieved in spite of manufacturing tolerances.